Diffusion and Osmosis Lab Flashcards

Questions and Answers

What is the purpose of today's laboratory?

To observe the effects of osmosis and diffusion on a model cell membrane with varying environments (varying concentrated solutions).

Define diffusion.

Diffusion is the tendency to go from an area of higher concentration to lower concentration.

Define osmosis.

Osmosis is the diffusion of water on a selectively permeable membrane to reach equilibrium.

What will the Benedict's test show when the water in the beaker is tested 15 minutes later after placing a bag of 15% glucose and 1% starch into water?

Benedict's test will appear positive for the water in the beaker; because the glucose will disperse into the beaker. Signup and view all the answers

What will happen when bags with different concentrations of sucrose are placed in water?

There will be osmosis but no diffusion. Signup and view all the answers

What is your dependent variable when measuring the percent change in mass of bags of sucrose?

Amount of water that moves into the bags. Signup and view all the answers

What is your independent variable when measuring the percent change in mass of bags of sucrose?

Sugar contents. Signup and view all the answers

What is % Change formula?

(Final mass - Initial mass)/(Initial mass) x 100. Signup and view all the answers

Define hypotonic.

Hypotonic: has a lower solute concentration than another. Signup and view all the answers

Define hypertonic.

Hypertonic: has a higher solute concentration than another. Signup and view all the answers

What happened in this lab?

A solution of glucose and starch are inside a bag of dialysis tubing and placed inside a beaker filled with distilled water. After thirty minutes has passed, the beaker will be tested for the presence of glucose and starch using Benedict's and Lugol's solution (IKI). Signup and view all the answers

Study Notes

Purpose of Laboratory

Aim is to study the effects of osmosis and diffusion on model cell membranes in various concentrated solutions.

Definitions

Diffusion: Movement from an area of higher concentration to lower concentration.
Osmosis: The diffusion of water across a selectively permeable membrane to achieve equilibrium.

Benedict's Test

A bag containing 15% glucose and 1% starch in a beaker of water will yield a positive result for glucose in the water after 15 minutes due to glucose dispersing.

Osmosis Predictions

When various bags with different sucrose concentrations are placed in water, osmosis will occur while diffusion of sucrose will not happen.

Variables in Experiment

Dependent Variable: The amount of water that enters the sucrose bags.
Independent Variable: The concentration of sugar (sucrose) in the bags.

Percent Change Calculation

Formula for percent change in mass: (Final mass - Initial mass) / (Initial mass) x 100.

Solution Concentration Definitions

Hypotonic: Solution with a lower solute concentration compared to another solution.
Hypertonic: Solution with a higher solute concentration compared to another solution.

Laboratory Procedure

Glucose and starch solutions are placed in a dialysis bag and submerged in distilled water.
After 30 minutes, tests using Benedict's and Lugol's solution are conducted to check for glucose and starch presence.
Initial mass of bags with varying sucrose concentrations (0.2 M, 0.4 M, 0.6 M, 0.8 M, 1.0 M) is recorded before submerging in distilled water for observation.

Description

Explore the essential concepts of diffusion and osmosis through engaging flashcards designed for a laboratory setting. Learn about the purpose of the lab and key definitions related to cell membranes and concentration gradients.